Davos in Switzerland is where the great ones of the world gather to sniff each other's aftershave. There you find more ego-stroking, back-scratching and mutual grooming than in the average colony of jungle apes. So when politicians, editors and tycoons excitedly echo one another in hailing the new democracy of the internet, and promise that it is upending the old order, a little scepticism is required. If they really thought they were about to be overthrown by bloggers, would they sound quite so cheerful about it?

Sitting next to Rupert Murdoch, whose global power depends on old-fashioned newspapers, television stations and cinema, Gordon Brown, whose power in Britain depends on old-fashioned voters, a party structure and parliamentarians, declared politics was now in the slow lane of the super-information highway, and would have to wise up.

"A few years ago the debate was about whether the media controlled politicians or whether politicians controlled the media. Now it is about how we are all responding to the explosive power of citizens, consumers and bloggers. The new focus on the environment is the result of that. The Make Poverty History campaign was the result of that. Citizens are flexing their muscles," he said.

Over in the US, the Democratic hopeful Hillary Clinton is promising to campaign for the presidency largely on the internet. David Cameron gained huge coverage in the old-world newspaper and TV media for his weblog. Every serious newspaper has dived into the internet age, even though it is not yet clear how they will raise the revenue they need as their print existence shrivels. Much of this is merely practical, the result of a technological shift nobody can halt or resist. But it comes with a grand-sounding manifesto about bringing in a new age of democracy, and that's really what needs to be questioned.

For instance, though it is true you can find out lots about global warming by Googling away, it not clear that our new environmental politics are much to do with the internet at all. They are clearly to do with hard work by serious scientists - and the campaigning of groups - which has persuaded politicians as it has been disseminated to the rest of us, including through films such as Al Gore's, books, and newspaper coverage for about a decade. Had the internet not existed, would we be worried about global warming, and would politics be responding to that? Of course.

Make Poverty History was an alliance which brilliantly used the internet. But even it depended on the old-style glamour of rock stars, the old-fashioned force of mass demonstrations, and the behind-the-scene backing of old-world politicians such as Brown. The super-information highway helped, but the cause of Africa pre-dated it, as the original Live Aid campaign, and the BBC news films by Michael Buerk, demonstrated. The net helped. It didn't create.

So what? Does it matter that politicians are getting a bit over-excited about the web? This is, after all, a wonderful new way of spreading ideas, information and argument. It has drawn plenty of people into political debate who would never have gone to a meeting, or even bothered to write a letter to a newspaper. It has allowed people who might never have visited a library to search out facts for themselves. Aren't citizens "flexing their muscles" as Brown says?

Well, yes and no. Some are. But the first thing to remember is that a large slice of the population is completely missing from this brave new internet world. According to the latest official figures, just under 14m households have internet access, or around 57%. This means 43% don't. And we know who they are - generally speaking, the poor and the old. There is also a clear geographical bias, with the south-east of England having 66% household use of the web, against lower figures in the north, falling to just 48% in Scotland.

That, though, is just the beginning. The vast majority of people using the internet are using it to communicate, look up friends, visit porn sites, play games or shop. The politically enfranchised, active internet community is very small indeed. If Guardian sites are any guide, bloggers tend to be disproportionately young, male, angry and rightwing. Busy parents, people working long hours and pensioners are rather less likely to be flexing their muscles by blogging or searching political sites.

Again, you could protest: isn't that just like pre-internet politics? Labour party meetings were always dominated by people who happened to have the time to get to them and - because they had to be motivated too - by people who were more committed and angrier than the average voter.

This is exactly the point. In the old days, nobody really thought Labour party meetings, or Tory constituency associations, were representative of the country at large. A party which wanted to win power had to search out and try to convert the others. The danger is that we forget that old lesson, and naively think of the internet and the bloggers as the only voice of the people. In practical terms, this could privilege the better-off and younger against the interests of working-class and older Britain. Old media - television, radio, newspapers and even meetings - all remain essential, and the old arguments about who controls the media remain as valid as ever. If Murdoch is lauding the internet it is because he is buying it up, trying to recreate digitally the monopolistic power he sought all his life in the paper, ink and broadcast world.

There are other dangers too. We should be nervous when politicians start boasting, as they are, that the net allows them to bypass irritatingly persistent, difficult interviewers such as John Humphrys and Jeremy Paxman. Obviously, they need to be scrutinised and cross-questioned by well-briefed interrogators, secure enough in their jobs to push the point. Democracy demands it. Putting up your own website, conducting online question-and-answer sessions, is a doddle by comparison. They allow the politician to control the terms of the exchange and never face a public challenge on questions they don't want to answer.

This is not a call to ignore the net or stop using the excellent research tools online. But we need to avoid easy hype. Most people are not cyber-citizens, they are living real, complicated lives in the real world. And that's where politicians should be too, rather than trying to surf off down the superhighway.